1. Field of the Invention
This invention relates generally to communication systems, and, more particularly, to wireless communication systems.
2. Description of the Related Art
Conventional wireless communication systems include numerous base stations that provide wireless connectivity to geographic areas that are commonly referred to as cells. Wireless connectivity may also be provided by access points, access networks, base station routers, and the like. Users access the wireless communication system using mobile units such as cellular telephones, personal data assistants, smart phones, pagers, text messaging devices, network interface cards, notebook computers, desktop computers and the like. For example, a user may initiate a call from a cellular telephone, which may establish a wireless communication link over and air interface between the telephone and one or more base stations that provide wireless connectivity to the cell containing the telephone. For another example, the user may subscribe to a multicast service (e.g., pay-per-view television) and the network may initiate a communication session with the user's mobile unit to provide the multicast service to the user.
Users are typically charged for the services provided by the conventional wireless communication system based on time and/or throughput associated with the services provided to the user's mobile unit. For example, users of cellular telephones are billed for the total duration of calls received by and/or placed by the user. The total call duration is often referred to as airtime usage. For another example, users of a multicast service such as streaming video and/or music or data services such as Internet access and/or e-mail may also be billed based upon the total data throughput required to provide these services. Some service providers offer service plans that allow a user access to unlimited minutes of airtime and/or unlimited data throughput. However, the rates for these “unlimited” service plans are based upon statistical estimates of the total airtime and/or data throughput that are expected for a typical user. Thus, the cash flow received by a service provider for each service is directly connected to the number of users that utilize the service, as well as how much of the service they use.
Service providers are beginning to offer applications and/or services that insure a particular Quality of Service (QoS) for the provided application. Call control and management for quality of service applications is significantly more complicated than regular packet data services that implement best-effort performance. For example, the service provider must guarantee certain levels of throughput, latency, jitter and loss in the packet stream provided by the application to insure a particular quality of service level for the end user. Furthermore, the guaranteed levels of throughput, latency, jitter and loss are different for each quality of service level and each application. Different quality of service applications may therefore consume different amounts of network resources, depending on the type of application, the number of users, and the quality of service levels requested by the users. For example, a user who requests a relatively high quality of service for an application such as video and/or audio streaming may require a relatively large proportion of network resources, such as time slots and/or radiofrequency power, to insure that the video and/or audio stream is received at the requested quality of service level. Similarly, a user who requests a relatively low quality of service for the audio and/or video streaming application may require a relatively smaller proportion of the network resources to achieve the relatively low quality of service.
Although service providers generally believe that quality of service applications should eventually be able to generate a large amount of revenue, the actual popularity of these services is not known. Consequently, service providers are not able to reliably predict demand for different quality of service applications and may therefore be unwilling to invest large amounts of capital to implement quality of service applications. Instead, service providers may prefer to adopt a “pay-as-you-grow” approach that enables them to increase capacity in response to demand for particular quality of service applications. In a conventional pay-as-you-grow approach, vendors provide hardware, firmware, and/or software that permit a selected airtime usage and/or data throughput for a given cost. Service providers may elect to pay more or less if the actual airtime usage and/or data throughput increases or decreases. For example, if the service provider has a license from a vendor that permits a data throughput of 10 kbps, but actual demand approaches or exceeds this level, the service provider may elect to pay more for a license that permits a data throughput of 20 kbps. However, vendors and/or service providers may not be able to implement a pay-as-you-grow approach for quality of service applications because the variability of resource usage for quality of service applications across multiple dimensions of resource demands (e.g., throughput, latency, jitter and loss) precludes a simplistic model of multiplicity based on throughput. Vendors and service providers may therefore not be able to reliably estimate a reasonable cost for different quality of service applications and levels.